React and Web API - How to submit form with files

I'm using React to develop the front and C # Web APIs for back.

I'm trying to submit a form that has an input file, in the API I created a ViewModel to receive this data. Before submitting, I put form data in a FormData , which is being filled correctly - I checked the console - however in the API the object always receives the empty values.

var data = new FormData();
data.append('IdMobileOperator', this.state.IdMobileOperator)
data.append('IdProductType', this.state.IdProductType)
data.append('TradeInDate', this.state.TradeInDate)
data.append('File', this.state.files)

$.ajax({
  url: url,
  type: 'POST',
  data: { simCards: data },
  processData: false,
  success: function (response) {
    //do something
  }.bind(this),
  error: function (response) {
    //do something else
  }
});

In the API, the action that receives the data is as follows:

[Route("Api/SimCard/Import")]
[HttpPost]
public async Task<HttpResponseMessage> ImportSimCard([FromBody]SimCardImportViewModel simCards)
{
   //do something
}

As it stands, the action is encountered by the request, but the object simCards has all the properties with no value - o when numeric, null when object, etc.